TCEQ Wastewater Collection
System Operator Class I — Form B
Exam QUESTIONS WITH CORRECT
ANSWERS PLUS RATIONALES
2026/2027 EDITION WITH INSTANT
PDF DOWNLOAD.
1. What is the primary purpose of a wastewater collection
system?
A. To treat wastewater before discharge
B. To provide drinking water to customers
C. To convey wastewater from its source to a treatment facility
D. To increase groundwater recharge
Rationale: A wastewater collection system is designed primarily
to collect and transport sewage from homes, businesses, and
other sources to a wastewater treatment facility. Treatment
processes occur after the wastewater reaches the treatment
plant.
2. Which type of sewer relies primarily on gravity to transport
wastewater?
A. Force main
B. Pressure sewer
C. Vacuum sewer
D. Gravity sewer
,Rationale: Gravity sewers are designed with sufficient slope so
wastewater flows downhill without continuous pumping. Proper
slope and hydraulic design are necessary to maintain adequate
flow velocities and reduce sediment deposition.
3. What is the primary function of a manhole in a wastewater
collection system?
A. To chemically disinfect wastewater
B. To increase wastewater pressure
C. To provide access for inspection, maintenance, and
cleaning
D. To remove dissolved oxygen
Rationale: Manholes provide personnel and equipment access to
underground sewer lines. They are commonly located at changes
in direction, changes in grade, junctions, and intervals along the
collection system.
4. Which condition is most likely to cause infiltration into a
wastewater collection system?
A. Improperly sized pumps
B. Cracked sewer pipes below the groundwater table
C. Excessive wastewater temperature
D. High dissolved oxygen
Rationale: Infiltration occurs when groundwater enters a
collection system through cracks, defective joints, deteriorated
manholes, or other openings. Infiltration can increase treatment
plant flows and place unnecessary hydraulic demands on the
system.
, 5. What does inflow refer to in a wastewater collection system?
A. Groundwater entering through pipe cracks
B. Industrial wastewater entering a treatment plant
C. Water entering the sewer system through direct
connections or openings
D. Treated wastewater returned to the collection system
Rationale: Inflow is water that enters a sanitary sewer through
sources such as roof drains, area drains, stormwater
connections, or improperly connected sump pumps. Unlike
infiltration, inflow generally enters through direct openings or
connections.
6. Why should grease accumulation be controlled in sanitary
sewer lines?
A. Grease increases dissolved oxygen
B. Grease improves pipe capacity
C. Grease can accumulate on pipe walls and restrict
wastewater flow
D. Grease disinfects the sewer
Rationale: Fats, oils, and grease can adhere to pipe walls and
progressively reduce the effective diameter of a sewer. Severe
accumulation can cause blockages, backups, and sanitary sewer
overflows.
7. What is a sanitary sewer overflow (SSO)?
, A. A controlled discharge from a treatment plant
B. A normal increase in wastewater flow
C. An unintended release of wastewater from a sanitary sewer
system
D. A discharge of drinking water from a water main
Rationale: An SSO occurs when wastewater escapes from the
sanitary sewer system through a manhole, cleanout, pipe, or other
location. SSOs can create environmental and public-health
concerns and require appropriate response and reporting.
8. Which practice is most effective for preventing excessive
sediment accumulation in a gravity sewer?
A. Eliminating manholes
B. Increasing pipe diameter without hydraulic analysis
C. Maintaining adequate flow velocity and conducting
preventive cleaning
D. Closing all upstream cleanouts
Rationale: Adequate velocity helps keep solids suspended and
moving through the sewer. Preventive inspection and cleaning
can also remove accumulated sediment before it causes
restrictions or blockages.
9. What is the purpose of a sewer cleanout?
A. To measure chlorine concentration
B. To aerate wastewater
C. To provide access for cleaning and maintenance
D. To increase groundwater infiltration
System Operator Class I — Form B
Exam QUESTIONS WITH CORRECT
ANSWERS PLUS RATIONALES
2026/2027 EDITION WITH INSTANT
PDF DOWNLOAD.
1. What is the primary purpose of a wastewater collection
system?
A. To treat wastewater before discharge
B. To provide drinking water to customers
C. To convey wastewater from its source to a treatment facility
D. To increase groundwater recharge
Rationale: A wastewater collection system is designed primarily
to collect and transport sewage from homes, businesses, and
other sources to a wastewater treatment facility. Treatment
processes occur after the wastewater reaches the treatment
plant.
2. Which type of sewer relies primarily on gravity to transport
wastewater?
A. Force main
B. Pressure sewer
C. Vacuum sewer
D. Gravity sewer
,Rationale: Gravity sewers are designed with sufficient slope so
wastewater flows downhill without continuous pumping. Proper
slope and hydraulic design are necessary to maintain adequate
flow velocities and reduce sediment deposition.
3. What is the primary function of a manhole in a wastewater
collection system?
A. To chemically disinfect wastewater
B. To increase wastewater pressure
C. To provide access for inspection, maintenance, and
cleaning
D. To remove dissolved oxygen
Rationale: Manholes provide personnel and equipment access to
underground sewer lines. They are commonly located at changes
in direction, changes in grade, junctions, and intervals along the
collection system.
4. Which condition is most likely to cause infiltration into a
wastewater collection system?
A. Improperly sized pumps
B. Cracked sewer pipes below the groundwater table
C. Excessive wastewater temperature
D. High dissolved oxygen
Rationale: Infiltration occurs when groundwater enters a
collection system through cracks, defective joints, deteriorated
manholes, or other openings. Infiltration can increase treatment
plant flows and place unnecessary hydraulic demands on the
system.
, 5. What does inflow refer to in a wastewater collection system?
A. Groundwater entering through pipe cracks
B. Industrial wastewater entering a treatment plant
C. Water entering the sewer system through direct
connections or openings
D. Treated wastewater returned to the collection system
Rationale: Inflow is water that enters a sanitary sewer through
sources such as roof drains, area drains, stormwater
connections, or improperly connected sump pumps. Unlike
infiltration, inflow generally enters through direct openings or
connections.
6. Why should grease accumulation be controlled in sanitary
sewer lines?
A. Grease increases dissolved oxygen
B. Grease improves pipe capacity
C. Grease can accumulate on pipe walls and restrict
wastewater flow
D. Grease disinfects the sewer
Rationale: Fats, oils, and grease can adhere to pipe walls and
progressively reduce the effective diameter of a sewer. Severe
accumulation can cause blockages, backups, and sanitary sewer
overflows.
7. What is a sanitary sewer overflow (SSO)?
, A. A controlled discharge from a treatment plant
B. A normal increase in wastewater flow
C. An unintended release of wastewater from a sanitary sewer
system
D. A discharge of drinking water from a water main
Rationale: An SSO occurs when wastewater escapes from the
sanitary sewer system through a manhole, cleanout, pipe, or other
location. SSOs can create environmental and public-health
concerns and require appropriate response and reporting.
8. Which practice is most effective for preventing excessive
sediment accumulation in a gravity sewer?
A. Eliminating manholes
B. Increasing pipe diameter without hydraulic analysis
C. Maintaining adequate flow velocity and conducting
preventive cleaning
D. Closing all upstream cleanouts
Rationale: Adequate velocity helps keep solids suspended and
moving through the sewer. Preventive inspection and cleaning
can also remove accumulated sediment before it causes
restrictions or blockages.
9. What is the purpose of a sewer cleanout?
A. To measure chlorine concentration
B. To aerate wastewater
C. To provide access for cleaning and maintenance
D. To increase groundwater infiltration
